The present invention relates to managing utilization of one or more physical processors in a shared processor pool, and more specifically, to managing utilization of one or more physical processors at least partially determined by a current amount of utilization of the one or more physical processors.
LPARs in a virtualized environment may be configured in uncapped mode and may use more virtual processors than entitlement. This assures that the LPAR itself is not limited by its entitled number of virtual processors in the case that the demand on physical processor or central processing unit (CPU) usage becomes higher than anticipated. A limiting factor is the availability of physical processors in a shared pool of CPUs or processors.
A disadvantage of such a configuration is that it typically results in a situation where the number of virtual processors configured on a system exceeds the number of physical processors in the shared processor pool. Virtual processor management in an operating system, such as AIX, may prevent all configured virtual processors of the LPARs from being active when the demand on CPU cycles is low, also known as processor folding. However, an increase in CPU demand can lead to a situation where enough virtual processors become enabled that the shared processor pools become depleted, even though the individual LPARs are not consuming all the CPU capacity assigned to them.